Fuel compositions comprising a combination of oxy compounds and ashless dispersants

ABSTRACT

Fuel compositions containing an additive combination comprising an oxy compound and a dispersant. Oxy compounds include glycol, polyglycols, and carboxylic acid esters thereof and carboxylic acid esters of monoethers of glycols and polyglycols. The dispersants are the esters, amides, imides, amidines, amine salts, and mixtures thereof of carboxylic acids characterized by the presence of at least about 30, but preferably at least 50, aliphatic carbon atoms in the acyl moiety. Solutions of such additive combinations are also disclosed. The fuels and solutions can be used to clean fuel systems in liquid-fuel burning devices such as internal combustion engines.

United States Patent I Dorer, Jr.

[is] 3,658,495 51 Apr. 25, 1972 [72] Inventor: Casper J. Dorer, Jr.,Lyndhurst, Ohio [73] Assignee: The Lubrlzol Corporation, Wickliffe, Ohio[22] Filed: Jan. 21, 1969 211 Appl. No.: 792,746

Related 1.1.8. Application Data I [63] Continuation-impart of Ser. No.749,948, Aug. 5,

1968, abandoned.

[52] [1.8. CI ...44/63, 44/66, 44/70, 44/71, 44/77 [51] Int. Cl...C1011/22 [58] Field of Search ..44/60, 70, 71, 77, 57, 63; v252/515 A[56] References Cited UNITED STATES PATENTS 2,104,021 1/1938 Callis..44/56 P X 2,527,889 10/1950 Moore et a1. ..44/66 2,548,347 4/1951Caron et a1. ..44/66 2,786,745 3/1957 Stayner et a1. ..44/77 Foreman..44/77 3 ,O47,373 7/1962 McGuire ..44/ 66 3,194,812 7/1965 Norman etal. ..252/51.5 A 3,219,666 11/1965 Norman et a1. ..252/51.5 A 3,340,2819/1967 Brannen, .lr ..252/51.5 A 3,381,022 4/1968 Le Seur ..-...252/5l.5A

Primary Examiner-Daniel E. Wyman Assistant Examiner-Mrs. Y. H. SmithAttorney-Roger Y. K. Hsu, William H .Pittman and James W. Adams, Jr.

57 ansrrucr characterized by the presence of at least about 30, but 1preferably at least 50, aliphatic carbon atoms in the acyl moiety.Solutions of such additive combinations are also disclosed. The fuelsand solutions can be used to clean fuel systems in liquid-fuel burningdevices such as internal combustion engines.

18 Claims, No Drawings tion is concerned with fuel'compositions andmethods for cleaning the fuel systemsof liquid fuel-buming engines andother fuel-buming devices such as furnaces. This invention is based uponthe discovery that certain oxy compounds in combination with certaindispersants are very usefulin inhibiting and removing sludge and otherdeposits which accumulate in such fuel systems. As is well known, themeans for eliminating and inhibiting the formation of undesirabledeposits within the fuel systems of engines and the like are constantlybeing sought.

In accordance with the foregoing, it is a principalobject of thisinvention to provide novel fuel compositions.

Another object is to provide fuel compositions containing an additivecombination consisting of oxy compounds and. certain dispersants.

A still further object of this invention is to provide methods forcleaning the fuel systems of internal combustion engines and otherliquid-fuel burning devices through the use of the additivecombination-of this invention.

These as well as other objects of this invention are achieved byproviding fuel compositions comprising a'major amount of at least onenormally liquid fuel, generally a petroleum distillate fuel, and a minoramount of an additive combination soluble in said fuel, the additivecombination comprising at least one" oxy compound selected. 'from' theclass consisting of glycols, polyglycols, and the carboxylic acid estersof these glycols, polyglycols, and their monoethers with monocarboxylicacid containing up to about twenty carbon atoms, and at least onefuel-soluble dispersant selected from the class consisting of esters,amides, imides, amidines, and amine salts of at least one substantiallysaturated carboxylic acid characterized by the presence within the acylradical thereof of at least 30 aliphatic carbon atoms; the weight ratioof oxy compound to dispersant being about 1:.10 to about 'l02l. Themethod for cleaning fuel systems as contemplated by this invention isreadily achieved by contacting fuel compositions of this type with atleast the internal surfaces of said fuel systems. The cleaning methodcan also be accomplished by using the additive combination in the formof a non-fuel solution thereof as a cleaning material.

The additive combination used in the fuel compositions of this inventionconsists of two essential components: at least one oxy compound and atleast one ashless dispersant. The ad-' ditive combination may bedissolved in a mutual solvent prior to adding it to the fuel althoughthis is not essential and the additive components can be added directlyto the fuel composition. Obviously, the additive combination should besoluble in the particular fuel in which it is to be used. However, thesolubility of the combination usually presents no problem since thedispersants are readily soluble in the fuels and the oxy .compounds areat least partially soluble in the fuel. However,

one of the attributes of the additive combination is that thedispersants promote the increased solubility of the oxy compounds sothat a combination of the dispersant and oxy compound is soluble in fueleven though the oxy compound alone may not be sufficiently soluble.Furthermore, the weight ratio of the oxy compound and dispersant isflexible so that the amount of each can be varied greatly in order toachieve solubility of an additive combination for a given fuelcomposition. The oxy compounds contemplated as components in theadditive combination in this invention are well known in the art and canbe readily synthesized according to known procedures or obtainedcommercially from various chemical suppliers. The term glycol" as usedin the present specification and claims is intended to describe dihydricorganic compounds of the formula HOR,--OH wherein R, is a divalenthydrocarbon or substituted hydrocarbon radical. Thus, R, can

tion of one of these wherein ;the substitue nt is lower alkyl, loweralkoxy, nitro, halo, oxo, and 'the like. Representative substitutedradicals would include 2-(ethoxy)-hexamethylene; 3-chloro-phenylene-l,3;2-(methoxy)-phenylene-l ,4; and 4- (nbutoxy)-cyclohexylene-l,2. However,from the standpoint of availability and economy, it is preferred thatthe R, variable be a divalent hydrocarbon radical, particularly analiphatic hydrocarbon radical.

The terminology .polyglycols" as used in the present specification andclaims is intended to describe the polyethers prepared from suchglycols. Thus, the polyglycols could be represented by the formulano-alo-an -on where each R, is independently a divalent radical of thetype These monoethers can be represented by the formula It, nltirt and OR|H\v( Rq/m Oll wherein R,, is a rnonovalent hydrocarbon or substitutedhydrocarbon radical and R, and m are as defined above. Thus, R, can bean aliphatic, cycloaliphatic, or aromatic hydrocarbon groupor asubstituted hydrocarbon group of this type wherein the substituents arethe same as those mentioned above in the case of R',. Again, R,, willusually be a hydrocarbon radical, particularly an alkyl radical or aphenyl radical including alkyl phenyl radicals. Illustrative examples ofR include methyl, ethyl, propyl, isopropyl, butyl, tertiary butyl,pentyl, hexyl, heptyl, octyl, nonyl, decyl, phenyl, benzyl, tolyl,xylyl, phenethyl, p-methoxy-phenyl, cyclohexyl, cyclopentyl, and thelike.

' The esters of the foregoing glycols, polyglycols, and their monoethersare illustrated by compounds corresponding towhere R, is a hydrocarbonor substituted hydrocarbon radical of up to'l9 carbon atoms.Illustrative examples of the radical R include formyl, acetyl,propionyl, and the corresponding acyl radicals derived from such acidsas acetic, propionic, butyric, valeric, caproic, enanthic, caprylic,pelargonic, capric, lauric, myristic, palmitic, stearic, isostearicbenzoic, and phenylacetic acid or cyclopentyl or cyclohexyl carboxylicacids and the like. Preferably the acyl radical is derived from analiphatic monocarboxylic acid, particularly alkanoic acids. The loweralkanoic monocarboxylic acids are especially preferred group of acids.

A particularly preferred class of oxy compounds is represented by theformula where n is such that the average molecular weight of the oxycompounds is not greater than about 1,200, each R is independentlyselected from the class consisting of hydrogen or a monocarboxylic acidacyl radical of up to about twenty carbon atoms and R is hydrocarbyleneof up to about eight carbon atoms. The hydrocarbylene groups may bealiphatic, cycloaliphatic or aromatic groups. Preferably, however, thehydrocarbylene groups will be branched or straight chain saturatedaliphatic groups. An especially preferred class of oxy compounds arethose corresponding to the above formula wherein n is 0, 1, 2, or 3,each R is independently H or acyl with the proviso that at least one Rvariable is acyl and R' is alkylene of up to about eight carbon atoms.

Specific examples of oxy compounds falling within the ambit of the aboveformulae are ethylene glycol, propylene glycol, trimethylene glycol,alpha-butylene glycol, 1,3-butanediol, beta-butylene glycol, isobutyleneglycol, tetramethylene glycol, hexylene glycol, diethylene glycol,dipropylene glycol, tripropylene glycol, triethylene glycol,tetraethylene glycol, 1,5-pentanediol, 2-methyl-2-ethyl-1,3- propanediol, 2-ethyl-l,3-hexanediol, the carboxylic acid esters thereof asdescribed above and the corresponding esters of their monoesters, e.g.,ethylene glycol mono phenyl ether, ethylene glycol mono methyl ether,ethylene glycol mono ethyl ether, ethylene glycol mono n-butyl ether,diethylene glycol mono methyl ether, diethylene glycol mono ethyl ether,diethylene glycol mono n-butyl ether, propylene glycol mono methylether, dipropylene glycol mono methyl ether, tripropylene glycol monomethyl ether, ethylene glycol mono isopropyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono hexyl ether, triethylene glycolmono butyl ether, triethylene glycol mono methyl ether, triethyleneglycol mono ethyl ether, l-butoxyethoxy-2propanol, polypropylene glycolhaving an average molecular weight of about 9754075, monophenyl ether ofpolypropylene glycol wherein the polyglycol has an average molecularweight of about 400-450 monophenyl ether of polypropylene glycol whereinthe polypropylene glycol has an average molecular weight of 975-1075.Specific esters include acrylic acid ester of 2- ethoxy-ethanol, valericacid diester of diethylene glycol, ethylene glycol diacetate, ethyleneglycol monoacetate, the dicaproic acid ester of diethylene glycol, andthe like. Such oxy compounds are sold in commerce under such names asButyl CELLOSOLVE, Ethyl CELLOSOLVE, Hexyl CEL- LOSOLVE, DOWANOL GlycolEthers, and the like. Such compounds are also disclosed in U.S. Pat.Nos. 2,089,580; 2,786,745; 2,807,525; 2,807,526; 2,914,479, 3,030,939;3,061,420; etc.

The second essential component of the additive combination is thedispersant. These dispersants are the esters, amides, imides, amidinesand amine salts of certain high molecular weight mono and polycarboxylicacids, these carboxylic acids being characterized by the presence withinthe acyl moieties thereof of at least about thirty aliphatic carbonatoms. These dispersants are well known to those skilled in the art andhave achieved widespread use in recent years as ashless additives forlubricating oils. Dispersants of this type and methods for theirpreparation are disclosed in detail in the following U.S. Pat. Nos.3,172,892; 3,184,474; 3,194,814; 3,194,812; 3,219,666; 3,272,746;3,340,281; 3,341,542; 3,347,645; 3,361,673; 3,381,022; British patent981,850; British patent 1055 ,337. For the sake of brevity, thesepatents are expressly incorporated herein for their disclosure ofashless dispersants and processes for preparing them. Generally, thesedispersants are prepared by reacting a mono or polycarboxylic acidacylating agent with a suitable hydroxyor amino-compound.

As disclosed in the above incorporated patents, there are severalprocesses for preparing the acylating agents. Generally, the processinvolves the reaction of 1 an ethylenically unsaturated carboxylic acid,acid halide, acid ester, or anhydride with (2) an ethylenicallyunsaturated hydrocarbon containing at least about 50 aliphatic carbonatoms or a chlorinated hydrocarbon containing at least about 30aliphatic carbon atoms at a temperature within the range of about l00300C. The chlorinated hydrocarbon or ethylenically unsaturated hydrocarbonreactant can, of course, contain polar substituents, oil-solubilizingpendant groups, and be unsaturated within the general limitationsexplained hereinabove. It is these hydrocarbon reactants which providesmost of the aliphatic carbon atoms present in the acyl moiety of thefinal products.

When preparing the carboxylic acid acylating agent according to one ofthese two processes, the carboxylic acid reactant usually corresponds tothe formula R,,(COOH where R, is characterized by the presence of atleast one ethylenically unsaturated carbon-to-carbon covalent bond and nis an integer from i to 6 and preferably 1 or 2. The acidic reactant canalso be the corresponding carboxylic acid halide, anhydride, ester(usually the lower alkyl esters) or other equivalent acylating agent andmixtures of one or more of these. Ordinarily, the total number of carbonatoms in the acidic reactant will not exceed 10 and generally will notexceed 6. Preferably the acidic reactant will have at least oneethylenic linkage in an a :position with respect to at least onecarboxyl function. Exemplary acidic reactants are acrylic acid,methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconicacid, itaconic anhydride, citraconic acid, citraconic anhydride,mesaconic acid, glutaconic acid, chloromaleic acid, aconitic acid,crotonic acid, methylcrotonic acid, sorbic acid, 3-hexenoic acid,IO-decenoic acid, and the like. Due to such considerations as economy,availability, reactivity, and performance of the products, the acidreactants usually employed are a unsaturated mono and dicarboxylicacids, particularly fumaric acid, and maleic anhydride, acrylic acid,and methacrylic acid.

The carboxylic acid acylating agents may contain cyclic and/or aromaticgroups. However, the acids are preferably essentially aliphatic innature. The most preferred acylating agents are the aliphatic carboxylicacids, anhydrides, esters or halides, usually the chlorides.

The substantially saturated aliphatic hydrocarbon-substituted succinicacids and anhydrides are especially preferred as acylating agents. Thesesuccinic acid acylating agents are readily prepared by reacting maleicanhydride with a high molecular weight olefin or a chlorinatedhydrocarbon such as a chlorinated polyolefin. The reaction involvesmerely heating the two reactants at a temperature of about l00-300 C.,preferably, l00-200 C. The product from such a reaction is a substitutedsuccinic anhydride where the substituent is derived from the olefin orchlorinated hydrocarbon as described in the above cited patents. Theproduct may be hydrogenated to remove all or a portion of anyethylenically unsaturated covalent linkages remaining by standardhydrogenation procedures, if desired. The substituted succinicanhydrides may be hydrolyzed by treatment with water or steam to thecorresponding acid and either the anhydride or the acid may be convertedto the corresponding acid halide or ester by reacting with phosphorushalide or lower alkanols.

The ethylenically unsaturated hydrocarbon reactant and the chlorinatedhydrocarbon reactant used in the preparation of the acylating agents areprincipally the high molecular weight, substantially saturated petroleumfractions and substantially saturated olefin polymers and thecorresponding chlorinated products. The polymers and chlorinatedpolymers derived from mono-olefins having from two to about 30 carbonatoms are preferred. The especially useful polymers are the polymers ofl-mono-olefins such as ethylene, propylene, l-butene, isobutene,l-hexene, l-octene, 2-methyl-1-heptene, 3- cyclohexyl- 1 -butene, and2-methyl-5-propyl- 1 -hexene. Polymers of medial olefins, i.e., olefinsin which the olefinic linkage is not at the terminal position, likewiseare useful. These are exemplified by 2-butene, 3-pentene, and 4-octene.

The interpolymers of l-mono-olefins such as illustrated above with eachother and with other interpolymerizable olefinic substances such asaromatic olefins, cyclic olefins, and polyolefins, are also usefulsources of the ethylenically unsaturated reactant. Such interpolymersinclude for example, those prepared by polymerizing isobutene withstyrene, isobutene with butadiene, propene with isoprene, propene withisobutene, ethylene with piperylene, isobutene with chloroprene,isobutene with p-methyl-styrene, l-hexene with 1,3-hexadiene, l-octenewith l-hexene, l-heptene with l-pentene, 3- methyl-l-butene withl-octene, 3,3-dimethyl-l-pentene with l-hexene, isobutene with styreneand piperylene, isobutene with propylene, etc.

For reasons of oil-solubility and stability, the polymers contemplatedfor use in preparing the acylating agents of this invention should besubstantially aliphatic and substantially saturated, that is, theyshould contain at least about 80 percent and preferably about 95percent, on a weight basis, of units derived from aliphaticmono-olefins. They usually will contain no more than about 5 percent,preferably no more than about 2 percent, olefinic linkages based on thetotal number of the carbon-to-carbon covalent linkages present therein.

The chlorinated hydrocarbons and ethylenically unsaturated hydrocarbonsused in the preparation of the acylating agents can have molecularweights of from about 300 up to about 10,000. The above describedpolyolefins and chlorinated polyolefins having an average molecularweight of about 400-to about 5,000 are preferred for preparing theacylating agents while those having molecular weights of about 700 toabout 3000 are especially preferred. Polypropylene, polyisobutylene,copolymers of propylene and isobutylene and their chlorinatedderivatives are particularly useful for reacting with theunsaturated'acid compound to prepare suitable acylating agents. Othermethods for preparing suitable carboxylic acid acylating agents usefulas intermediates in the synthesis of the dispersants are disclosed inthe above-incorporated patents.

The dispersants are prepared by reacting at least one of theabove-discussed acylating agents with a suitable hydroxyl compound oramino compound characterized by the presence within its structure of atleast one-NH group. When the acylating agents are reacted with hydroxylcompounds, esters are produced whereas reaction with amino compoundsproduces amides, imides, amidines, amine salts, or mixtures thereof. Ifthe reactant contains both hydroxyl and amino groups, the reactionmixture is usually a mixture of esters and acylated nitrogen compounds,i.e., amides, imides, amine salts, etc. Similarly, the acylating agentscan be reacted with a mixture of hydroxyl compounds and amino compoundsas disclosed in U.S. Pat. No. 3,184,474.

A preferred group of ester dispersants are those prepared from thepolyolefin-substituted succinic acids or chlorinatedpolyolefin-substituted succinic acids and polyhydric alcohols containingup to about forty aliphatic carbon atoms and two-ten hydroxyl groups.The esters can be the mono or diesters or mixtures thereof. Esters ofpolyisobutenyl-substituted succinic acid and ethylene glycol, glycerol,pentaerythritol, mannitol, sorbitol, and the like are illustrative ofthis class of esters. Esters of this type are described in detail inU.S. Pat. No. 3,381,022 and British patents 981,850 and 1,055,337.

However, for purposes of this invention, the dispersant is preferablyone prepared by reacting at least one of the above described acylatingagents with an amino compound. As disclosed in U.S. Pat. No. 3,219,666,the amino compounds can be quite diversified and include aliphatic,cycloaliphatic, aromatic, and heterocyclic amines. These are exemplifiedby N- methyloctyl amine, N-cyclohexyl aniline, cyclohexyl amine,aniline, dodecyl amine, morpholine, piperazine, ethanol amine, phenolhydrazine, octadecyl hydrazine, urea, N-butyl urea, dicyan diamide, andthe like. Generally, however, the amine is an alkylene polyamine. Thedispersants of the present invention also include the reaction productsof acylated nitrogen compounds prepared by reacting the above acylatingagents with these amino compounds and other materials such as boronreactants as disclosed in U.S. Pat. No. 3,087,936;

carbon disulfide as disclosed closed in U.S. Pat. No. 3,200,107,.alkeny1cyanide such as disclosed in U.S. Pat. No. 3,278,550; epoxides asdisclosed in U.S. Pat. No. 3,373,111; dicarboxylic acids as disclo'sedin U.S. Pat. No. 3,374,174; monocarboxylic acids such as illustrated inU.S. Pat. Nos. 3,185,704 and 3,216,936; and aldehydes and ketones asdisclosed in British Patent Specification 1,106,227. This lastspecification also discloses the reaction of these acylated aminematerials with other reactive agents such as carboxylic acids, urea,thiourea, guanidine and boric acid. Again, for the sake of brevity,these patents are incorporated herein by reference for their disclosureof these various dispersants prepared from acylating agents and aminocompounds. For the most part, these dispersants can be described asoil-soluble acylated nitrogen compounds characterized by the presencewithin their structure of a substantially saturatedhydrocarbon-substituted polar group selected from the class consistingof acyl, acylimidoyl, and acyloxy radicals wherein the substantiallysaturated hydrocarbon substituent contains at least about thirtyaliphatic carbon atoms and a nitrogen-containing group characterized bya nitrogen atom attached directly to said polar radical.

The preferred dispersants are those prepared from monocarboxylic acidacylating agents and polyolefin substituted or chlorinated substitutedsuccinic acids or anhydrides and alkylene polyamines. The polyolefinsubstituent can be hydrogenated according to known procedures to producealkyl substituents if desired. The preparation of such compounds isdisclosed in detail in U.S. Pat. Nos. 3,172,892; 3,219,666; 3,361,673;and 3,272,746. These especially preferred dispersants are prepared byreacting a monocarboxylic acid acylating agent or the substitutedsuccinic acid acylating agent with an alkylene polyamine of the formulaMHZ. where q is an integer of I9 and Z is lower alkyl or H in a ratio ofacylating agent to alkylene polyamine of one equivalent of acylatingagent to one equivalent of alkylene polyamine to about one equivalent ofacylating agent to one mole of alkylene polyamine. The reaction isgenerally conducted by heating a mixture of the acylating agent and thealkylene polyamine at a temperature of above about C. and preferablywithin the range of C. to about 250 C. The reaction may be conducted inthe presence of a solvent such as benzene, toluene, naphtha, mineraloil, xylene, n hexane, chlorobenzene, and the like. The reaction productis generally a mixture of amides, imides, amidines, and amine salts.Generally, however, if the reaction temperature is at least 100 C., theproducts consist essentially of the amides, imides, or amidines.

The alkylene polyamines from which the dispersants are preparedgenerally have less than eight carbon atoms in the alkylene moiety andusually two to four carbon atoms in the alkylene moiety. These alkyleneamines include methylene amines, ethylene amines, propylene amines,butylene amines,

pentylene amines, hexylene amines, and the like. Illustrative of thisclass of alkylene polyamines are ethylene diamine, triethylenetetramine, propylene diamine, decarnethylene diamine, octamethylenediamine, di(heptamethylene)triarnine, tripropylene tetramine,tetraethylene pentamine, pentaethylene hexamine, trimethylene diamine,diethylene triamine, and the like.

The ethylene polyamines are particularly preferred for preparing thedispersants. Included within the class of these ethylene polyamines arethe commercially available mixtures of such ethylene polyamines preparedby the reaction of an alkylene chloride with ammonia. This reactionproduct consists of a mixture of ethylene polyamine such astetraethylene pentamine, triethylene tetramine, diethylene triamine,pentaethylene hexamine, and the like as well as cyclic derivatives suchas N-aminoethyl-piperazine, and the like. i

Basic dispersants are particularly suitable in the additive combinationof this invention. These basic dispersants are those prepared from areaction mixture wherein the equivalent ratio of acylating agent toalkylene polyamine is at least 1:1.05. These basic dispersants areprepared generally by reacting the carboxylic acid acylating agents andthe alkylene polyamines in a ratio of 1:1.1 to about 1:3.

For purposes of this invention, the number of equivalents in an aminereactant is that number of NH groups present therein. Similarly, anacylating agent has a number of equivalents per molecule correspondingto the number of carboxy groups [I II (or C halo, C- o allryl, etc.)

present. Thus, ethylene diamine has two equivalents;polyisobutenyl-substituted succinic acid, two; polyisobutenylsubstitutedacrylic, one; tetraethylene pentamine, five; etc.

As mentioned hereinbefore, the fuel compositions of this invention canbe prepared from solutions of the oxy compounds and the dispersants.Solvents useful in preparing such solutions are the normally liquid,substantially inert organic compounds such as the aliphatic,cycloaliphatic and aromatic hydrocarbons and chlorinated hydrocarbons,ethers, naphthas, mineral oils, N,N-dialkyl lower alkanoic acid amines,and the like. Illustrative solvents include kerosene, SAE 10 mineraloil, benzene, toluene, xylene, chlorobenzene, methoxybenzenes,ethoxybenzenes, pentane, hexane, heptane, octane, nonane, decane,undecane, dodecane, cyclohexane, cyclopentane, N,N-dimethylformamide,N,N- dimethylacetamide, ethyl ether, propyl ether, isopropyl ether,butyl ether, isoamyl ether, isobutyl ether, methyl n-propyl ether,methyl isobutyl ether, methylamyl ether, ethyl n-butyl ether, and thelike. The best solvent or combination of solvents to be used with anyadditive combination will depend upon the particular dispersants, oxycompounds, and the fuel in which the additive is to be used. Generallyspeaking, the aromatic solvents particularly the aromatic hydrocarbonscontaining up to 12 carbon atoms such as benzene, toluene, xylene, andthe like and combinations of these with each other or with the othertypes of solvents produce the best results.

The fuel compositions of this invention will comprise a major amount ofa particular fuel and a minor amount of the additive combinationsdescribed hereinabove. Ordinarily, the additive combination will bepresent in an amount such that the total weight of dispersant and oxycompound present in the final fuel compositions will be from about 0.001to about 5 percent by weight of the total weight of fuel and additivecombination. A preferred concentration in fuels such as gasoline is 0.01to about 1 percent by weight.

However, solutions of the additive combination of this invention can beused directly as cleaning agents for fuel systems. In other words, theseadditive combinations in the form of solutions in one or more of theabove solvents can be used as a cleaning agent to clean the fuel systemsof various internal combustion engines and other liquid fuel burningdevices such as furnaces simply by contacting the internal surfaces ofthe fuel system with the solution. Since the combustion characteristicsof these cleaning compositions is unimportant as they are not themselvesto be burned, the additive combination can constitute a much largerportion of the cleaning composition, for example up to about 90 percentby weight of the total composition usually from about 5 percent up toabout 70 percent by weight of the composition. It will be apparent tothose skilled in the art, however, that even though such cleaningcompositions are not intended to be burned, they can utilize fuels assolvents for the additive combination. Therefore, diesel fuel, kerosene,and gasoline solutions of the additive combination are contemplated asbeing cleaning compositions falling within the scope of the presentinvention.

In accordance with the foregoing, this invention contemplates thecleaning of the fuel system components of internal combustion enginessuch as the carburetor, fuel lines, fuel tank, filters, fuel pumps, fuelinjectors, fuel metering devices, and the like either by employing afuel containing the additive combination of this invention so that theinternal surfaces of the various fuel system components can be cleanedby exposure to the additive combination in solution in the fuel or bycontacting the internal surfaces of these components with a cleaningsolution of the additive combination of this invention. It is alsocontemplated that the additive combination of this invention can be usedas a fuel system cleaner in the same manner as other additivecombinations presently on the market. That is, a solution of theadditive combination may be added directly to the carburetor during,before, or after engine operation.

Members of the preferred class of dispersants, that is those preparedfrom alkylene polyamines, can be prepared according to the processesillustrated by the following examples. Other dispersants of the typecontemplated by the present invention can be prepared according to theprocedures set forth in detail in the above-incorporated patents. Asused in the following examples and elsewhere herein, percentages andparts" refer to per cent by weight and parts by weight unless otherwiseindicated.

EXAMPLE 1 A polyisobutenyl succinic anhydride is prepared by thereaction of a chlorinated polyisobutylene with maleic anhydride at 200C. The polyisobutenyl radical has an average molecular weight of 850 andthe resulting alkenyl succinic anhydride is found to have an acid numberof 1 l3 (corresponding to an equivalent weight of 500). To a mixture of500 grams (1 equivalent) of this polyisobutenyl succinic hydride and 160grams of toluene there is added at room temperature 35 grams (1equivalent) of diethylene triamine. The addition is made portionwisethroughout a period of l5 minutes, and an initial exothermic reactioncaused the temperature to rise to 50 C. The mixture then is heated and awater-toluene azeotrope distilled from the mixture. When no more waterwould distill the mixture is heated to 150 C. at reduced pressure toremove the toluene. The residue is diluted with 350 grams of mineral oiland this solution is found to have a nitrogen content of 1.6 percent.

EXAMPLE 2 The procedure of Example 1 is repeated using 55.5 grams (l.5equivalents) of an ethylene amine mixture having a compositioncorresponding to that of triethylene tetrar'nine. The resulting producthas a nitrogen content of 1.9 percent.

EXAMPLE 3 To a mixture of grams of toluene and 400 grams (0.78equivalent) of a polyisobutenyl succinic anhydride (having an acidnumber of 109 and prepared from maleic anhydride and the chlorinatedpolyisobutylene of Example i) there is added at room temperature 62.6grams (1.55 equivalents) of an ethylene amine mixture having an averagecomposition corresponding to that of tetraethylene pentamine. Themixture is heated to distill the water-toluene azeotrope and then to C.at reduced pressure to remove the remaining toluene. The reactionproduct has a nitrogen content of 4.7 percent.

EXAMPLE 4 A mixture of 1056 grams (2.0 equivalents) of thepolyisobutenyl succinic anhydride of the preceding example (in which thepolyisobutenyl group has a molecular weight of 850), 89 grams (2.0equivalents) of di-( 1,2-propylene) triamine (having a nitrogen contentof 31.3 percent), 370 grams of mineral oil and 100 grams of toluene isheated at reflux temperature (l80-90 C.) for 5 hours. A total of 18grams of water is collected from the water-toluene azeotrope. Theresidue is heated to 150 C./20 mm. to remove any last traces of waterwhich might have remained. The nitrogen analysis of this residue is 1.9percent.

EXAMPLE A polypropylene substituted succinic anhydride having an acidnumber of 84 is prepared by the reaction of a chlorinated polypropylenehaving a chlorine content of 3 percent and molecular weight of 1,200with maleic anhydride. A mixture of 813 grams of thepolypropylene-substituted succinic, anhydride, 50 grams of a commercialethylene amine mixture having an average composition corresponding tothat of tetraethylene pentamine and 566 grarns of mineral oil is, heatedat 150 C. for 5 hours.'The residue is found to have a nitrogen contentof 1.18 percent.

' EXAMPLE 6 EXAMPLE 7.

A mixture of 2000 grams of mineral oil, 3 equivalents of trimethylenediamine and 3 equivalents of a high molecular weighttricarboxylic.acidprepared by the reaction of a brominated poly(l-hexene) having a. molecular weight. of

2,000 and a bromine contentof 4 percent by weight of2-pentene-l,3,5-tricarboxylic acid (prepared by dehydration of citricacid) is heated at 150 C. for 20 hours. The residue is filtered to givea homogeneous'mineral oil solution of the acylated nitrogen product.

' EXAMPLE 8 A product is obtained by the procedure of example 1, exceptthat tripentylene' tetramine (3 equivalents) is used in lieu oftheethylene diamine. w

EXAMPLE 9 A mixture of 386 grams of mineral'oil, 528 grams of thepolyisobutene-substituted succinic'anhydride of example 1, and 59 gramsof N-(2-hydroxyethyl)4rimethylene-diamine was prepared at 60 C. Themixture was blown with'nitrogen at l50-155 C. for 5 hours. The residuehad a nitrogen content of 1.56 percent.

EXAMPLE 10 was collected as the distillate. The residue was then heatedto 160 C./2$ mm. and diluted with 570 grams of mineral oil. The finalproduct was found to have a nitrogen content of 1.57 percent.

1.9 EXAMPLE 11 A substituted monocarboxylic acid acylating agent isobtained by reacting acrylic acid (1 equivalent) with a chlorinatedpolyisobutene (1 equivalent) having a' chlorine content of 4.5 percentand a, molecular weight of 850. at l50-200 C. The product of thereaction; is then mixed with 1.25 equivalents of pentaethylene hexamineat 5045," C. and

the resulting mixture is heated at l80-200 C. to form an acylatedpolyamine.

EXAMPLE 12 The procedure of Example 11 is repeated except that theacrylic acid is replaced on a chemically equivalent basis withalpha-chloroacrylic acid and the pentaethylene hexamine is replaced on anitrogen basis with ethylene diamine.

Fuel compositions contemplated by the present invention are illustratedby the following:

COMPOSITION A Gasoline containing 0.1 percent by weight of an. additivesolution of the present invention, said solution consisting essentiallyof about 50 percent by weight xylene, 25 percent by weight of a filtrateprepared according to Example 2 wherein the filtrate has a mineral oilcontent of about 40 percent by weight, and about 25 percent of theacetic acid ester of ethylene glycol mono-n-butylether.

COMPOSITION B Diesel fuel containing 0.5% of the filtrate of Example 7ad justed to an oil content of 40. percent and 0.75 percent of theZ-ethylhexinoic ether.

COMPOSITION C Gasoline containing 1.5 percent of a filtrate preparedfrom the product of Example 1 and adjusted to an oil content of 40COMPOSITION o Gasoline containing 0.05 percent of a solution consistingessenti'ally of about 50 percent by weight of xylene, about 25 percentby weight of a filtrate prepared according to the procedure of ExampleSand adjusted to an oil content of 40 percent, about 10 percent byweight of the acetic acid ester of ethylene glycol monophenyl ether, andabout 15 percent by weight of the butyric acid ester ethylene glycolmono-n-butyl ether.

By substituting other dispersants and other oxy compounds of the typedescribed hereinbefore for those in the above examples other fuelcompositions of the type contemplated by the present invention arereadily prepared. The solutions of the additive combinations of thisinvention which can be used directly ascleaning compositions areillustrated by those used in the preparation of the fuel compositions ofComposition A and D above. Similarly, by substituting other solvents ofthe type described hereinbefore for all or part of the xylene, othercleaning compositions can be readily prepared.

The additive combination of the present invention are particularlyvaluable since they coact synergistically in the cleaning of the fuelsystems. This synergistic effect is illustrated by the followingprocedure:

A clean steel test panel (5 7/8 in. X 1 5/16 in. X H16 in.) is immersedin a varnish solution (prepared byadding 2 percent by weight Enarcosludge to a solution of a 1:1 weight ratio of benzene and acetone) andis allowed to dry thoroughly. This is done three times. Then theprepared panel is used to stir ml. of the test solution in a 250 ml.beaker for five minutes. The amount of deposited sludge removed is ratedvisually and indicates the effectiveness of the test soluacid esterdipropylenc glycol monomethyl I Dispersant Mineral 011 Percent sludgeremoved Test composition number Oxy Concen: comtration Xylene pound(m1-) D Mineral oil solution (30% by weight oil) of a commerciallyavailable ashless dispersant prepared by reacting lylsobutenyl (averagemol. wt. 850l,l)-substituted succinic unhyd de and an ethylene polyaminemixture having on average of about five amino groups per molecule in anequivalent ratio of anhydride to polyamine 01 about 111.1 accordingo17t2h 92gcneral procedures described and illustrated in U.S. patentNMXNNNNNNN 0 O =CHs OCH2CH1OCHg- O O =CH: -OCHrCHzOCHrCHzOCHrCHt- O=CHgii-OCHzCHzOCHzCHgO(CHDsCHz.

From the foregoing test, it is clear that the combination of additivesprovides an amount of sludge reduction which is greatly in excess ofthat of either additive alone or the cumulative sludge reduction of bothadditives.

As will be apparent to those skilled in the art, the fuels used in thefuel compositions will normally be petroleum distillate fuels, such asfuel oils, diesel fuels, kerosene, gasolines, aviation fuels, etc.Furthermore, the fuel compositions of this invention may contain otherconventional additives such as smoke suppressants, alltyl lead antiknockagents, antistatic agents, corrosion inhibitors, antioxidants, antiicingagents, lead scavengers, lead octane appreciators, dyes, and the like.

What is claimed is:

l. A liquid fuel composition comprising a major amount of at least onenormally liquid fuel and a minor amount sufficient for inhibiting andremoving sludge and other deposits which accumulate in fuel systems, ofan additive combination soluble in said fuel, the additive combinationcomprising at least one oxy compound selected from the class consistingof glycols, polyglycols, and the carboxylic acid esters of theseglycols, polyglycols, and monoethers there of with monocarboxylic acidscontaining up to about carbon atoms, and at least one fuel-solubleashless dispersant selected from the class consisting of esters, amides,imides, amidines, and amine salts of at least one substantiallysaturated carboxylic acid characterized by the presence within itsstructure of at least about aliphatic carbon atoms; the weight ratio ofoxy compound to dispersant being about 1:10 to about 10:1.

2. A fuel composition according to claim 1 wherein said dispersant is anacylated nitrogen composition characterized by the presence within itsstructure of a substantially saturated hydrocarbon-substituted polargroup selected from the class consisting of acyl, acylimidoyl, andacyloxy radicals wherein the substantially saturated hydrocarbonsubstituent contains at least about thirty aliphatic carbon atoms and anitrogencontaining group characterized by a nitrogen atom attacheddirectly to said polar radical.

3. A fuel composition according to claim 1 containing from about 0.001to about 5 percent by weight of said additive combination wherein thedispersant is at least one ester, amide,

imide amidine, or amine salt of a polymerized olefin-substituted monoordicarboxylic acid or a chlorinated, polymerized olefin-substitutedmonoor dicarboxylic acid containing at least about thirty aliphaticcarbon atoms in the carboxylic acid moiety.

4. A fuel composition according to claim 3 where said at least one oxycompound corresponds to those represented by the formula:

where n is such that the average molecular weight of the oxy compound isnot greater than about 1,500, each R is independently selected from theclass consisting of H, hydrocarbyl of up to about eight carbon atoms, ora monocarboxylic acid acyl radical of up to about twenty carbon atoms,with the proviso that at least one R variable is an acyl radical and Ris hydrocarbylene of up to about eight carbon atoms.

5. A gasoline fuel composition according to claim 4 where n is 0, 1, 2,or 3, each R is independently H, phenyl, alkyl phenyl, or alkyl with theproviso that at least one R variable is an acyl radical of an aliphaticmonocarboxylic acid.

6. A gasoline fuel composition according to claim 5 wherein thedispersant is the reaction product of at least one of said substitutedmonoor dicarboxylic acids or their anhydrides and at least one alkylenepolyamine having up to about ten amino nitrogen atoms where the ratio ofsubstituted monoor dicarboxylic acid or anhydride and the alkylenepolyamine in the reaction mixture is from about one equivalent of acidor anhydride per equivalent of alkylene polyamine to about oneequivalent of acid or anhydride per mole of alkylene polyamine.

7. A gasoline fuel composition according to claim 6 wherein one R islower alkyl and the other R is a lower alkanoyl radica].

8. A gasoline fuel composition according to claim 7 wherein thedispersant is the reaction product of at least one polyisobutenylsubstituted-succinic acid or anhydride or a chlorinated polyisobutenylsubstituted-succinic acid or anhydride and at least one ethylenepolyamine having from two to six amino nitrogen atoms in the moleculesthereof, wherein the polyisobutenyl-substituted succinic acid oranhydride and the ethylene polyamine are reacted in an equivalent ratioof about 1:1 to about 1:3.

9. A gasoline fuel composition according to claim 8 wherein the oxycompound is the acetic acid ester of ethylene glycol monobutyl ether.

10. A fuel composition according to claim 1 wherein the normally liquidfuel is a petroleum distillate fuel.

11. A fuel composition according to claim 10 wherein the normally liquidfuel is a petroleum distillate fuel boiling in the gasoline range.

12. A fuel composition according to claim 1 wherein said additivecombination contains at least one substantially inert organic solventfor the said additive combination.

13. A fuel composition according to claim 12 wherein the solvent is anaromatic hydrocarbon.

14. A composition useful in the method for cleaning the fuel system of aliquid fuel burning internal combustion engine or liquid fuel burningheating device comprising contacting at least the internal surfaces ofsaid fuel system with a cleaning composition, said compositioncomprising a solution of (1 at least one oxy compound selected from theclass consisting of glycols, polyglycols, and the carboxylic acid estersof these glycols, polyglycols, and monoethers thereof withmonocarboxylic acids containing up to about twenty carbon atoms and (2)at least one fuel-soluble ashless dispersant selected from the classconsisting of esters, amides, imides, amidines, and amine salts of atleast one substantially saturated carboxylic acid characterized by thepresence within its structure of at least about thirty aliphatic carbonatoms, wherein the weight ratio of oxy compound to dispersant beingabout 1:10 to about 10:1, and (3) a solvent for the combination of (l)and (2) wherein the solvent for the combination of (l) and (2) is atleast'one normally liquid, substantially inert, organic compound, thetotal amount of the combination of (1) and (2) being from about 5 toabout 70 percent by weight of the total weight of composition.

15. The composition according to claim 14 wherein the oxy compoundscorrespond to the formula where n is such that the average molecularweight of the oxy compounds is not greater than about L500, each R isindependently selected from H, hydrocarbyl of up to about twelve carbonatoms, or a monocarboxylic acid acyl radical of up to about twentycarbon atoms with the proviso that at least one R variable is an acylradical, and R is hydrocarbylene of up to about eight carbon atoms; andwherein the dispersant is the reaction product of at least one acylatingagent selected from the class consisting of polymerizedolefin-substituted monoor dicarboxylic acid or chlorinated polymerizedolefin-substituted monoor dicarboxylic acid, or the lower alkyl esters,acyl halides, or anhydrides, of those containing at least about thirtyaliphatic carbon atoms in the carboxylic acid moiety with at least onealkylene polyamine having up to about ten amino nitrogen atoms whereinthe ratio of acylating agent to alkylene polyamine in the reactionmixture is from about one equivalent of acylating agent per equivalentof alkylene polyamines to about one equivalent of acylating agent toabout one mole of alkylene polyamine; and wherein the solvent is anormally liquid aromatic hydrocarbon.

16. A composition according to claim 15 wherein n is 0, l, 2, or 3, eachR is independently H, hydrocarbyl of up to about eight carbon atoms, ora monocarboxylic acid acyl radical of up to about twelve carbon atoms,with the proviso that at least one R variable is an aliphaticmonocarboxylic acid acyl radical, and R is alkylene of up to about eightcarbon atoms and wherein the dispersant is the reaction product obtainedby reacting at least one polyisobutenyl-substituted or chlorinatedpolyisobutenyl-substituted succinic acid or anhydride with an ethylenepolyamine.

17. A composition according to claim 16 wherein one R is alkyl and theother is lower alkanoyl and the dispersant is the reaction product of atleast one polyisobutenyl-substituted or chlorinatedpolyisobutenyl-substituted succinic acid or anhydride and an ethylenepolyamine having from two to six amino nitrogen atoms in the moleculesthereof wherein the succinic acid or anhydride and the ethylenepolyamine are reacted in an equivalent ratio of about 1:1 to about l:3,and wherein the solvent is at least one alkybsubstituted benzenecontaining up to 12 carbon atoms.

18, The method according to claim 17 wherein oxy compound is the aceticacid ester of ethylene glycol monobutyl ether.

2. A fuel composition according to claim 1 wherein said dispersant is anacylated nitrogen composition characterized by the presence within itsstructure of a substantially saturated hydrocarbon-substituted polargroup selected from the class consisting of acyl, acylimidoyl, andacyloxy radicals wherein the substantially saturated hydrocarbonsubstituent contains at least about thirty aliphatic carbon atoms and anitrogen-containing group characterized by a nitrogen atom attacheddirectly to said polar radical.
 3. A fuel composition according to claiM1 containing from about 0.001 to about 5 percent by weight of saidadditive combination wherein the dispersant is at least one ester,amide, imide amidine, or amine salt of a polymerized olefin-substitutedmono-or dicarboxylic acid or a chlorinated, polymerizedolefin-substituted mono- or dicarboxylic acid containing at least aboutthirty aliphatic carbon atoms in the carboxylic acid moiety.
 4. A fuelcomposition according to claim 3 where said at least one oxy compoundcorresponds to those represented by the formula: where n is such thatthe average molecular weight of the oxy compound is not greater thanabout 1,500, each R is independently selected from the class consistingof H, hydrocarbyl of up to about eight carbon atoms, or a monocarboxylicacid acyl radical of up to about twenty carbon atoms, with the provisothat at least one R variable is an acyl radical and R'' ishydrocarbylene of up to about eight carbon atoms.
 5. A gasoline fuelcomposition according to claim 4 where n is 0, 1, 2, or 3, each R isindependently H, phenyl, alkyl phenyl, or alkyl with the proviso that atleast one R variable is an acyl radical of an aliphatic monocarboxylicacid.
 6. A gasoline fuel composition according to claim 5 wherein thedispersant is the reaction product of at least one of said substitutedmono- or dicarboxylic acids or their anhydrides and at least onealkylene polyamine having up to about ten amino nitrogen atoms where theratio of substituted mono- or dicarboxylic acid or anhydride and thealkylene polyamine in the reaction mixture is from about one equivalentof acid or anhydride per equivalent of alkylene polyamine to about oneequivalent of acid or anhydride per mole of alkylene polyamine.
 7. Agasoline fuel composition according to claim 6 wherein one R is loweralkyl and the other R is a lower alkanoyl radical.
 8. A gasoline fuelcomposition according to claim 7 wherein the dispersant is the reactionproduct of at least one polyisobutenyl substituted-succinic acid oranhydride or a chlorinated polyisobutenyl substituted-succinic acid oranhydride and at least one ethylene polyamine having from two to sixamino nitrogen atoms in the molecules thereof, wherein thepolyisobutenyl-substituted succinic acid or anhydride and the ethylenepolyamine are reacted in an equivalent ratio of about 1: 1 to about 1:3.9. A gasoline fuel composition according to claim 8 wherein the oxycompound is the acetic acid ester of ethylene glycol monobutyl ether.10. A fuel composition according to claim 1 wherein the normally liquidfuel is a petroleum distillate fuel.
 11. A fuel composition according toclaim 10 wherein the normally liquid fuel is a petroleum distillate fuelboiling in the gasoline range.
 12. A fuel composition according to claim1 wherein said additive combination contains at least one substantiallyinert organic solvent for the said additive combination.
 13. A fuelcomposition according to claim 12 wherein the solvent is an aromatichydrocarbon.
 14. A composition useful in the method for cleaning thefuel system of a liquid fuel burning internal combustion engine orliquid fuel burning heating device comprising contacting at least theinternal surfaces of said fuel system with a cleaning composition, saidcomposition comprising a solution of (1) at least one oxy compoundselected from the class consisting of glycols, polyglycols, and thecarboxylic acid esters of these glycols, polyglycols, and monoethersthereof with monocarboxylic acids containing up to about twenty carbonatoms and (2) at least one fuel-soluble ashless dispersant selected fromthe class consisting of esters, amides, imides, amidines, and aminesalts of at least one substantially saturated carboxylic acidcharacterized by the presence within its structure of at least aboutthirty aliphatic carbon atoms, wherein the weight ratio of oxy compoundto dispersant being about 1:10 to about 10:1, and (3) a solvent for thecombination of (1) and (2) wherein the solvent for the combination of(1) and (2) is at least one normally liquid, substantially inert,organic compound, the total amount of the combination of (1) and (2)being from about 5 to about 70 percent by weight of the total weight ofcomposition.
 15. The composition according to claim 14 wherein the oxycompounds correspond to the formula where n is such that the averagemolecular weight of the oxy compounds is not greater than about 1,500,each R is independently selected from H, hydrocarbyl of up to abouttwelve carbon atoms, or a monocarboxylic acid acyl radical of up toabout twenty carbon atoms with the proviso that at least one R variableis an acyl radical, and R'' is hydrocarbylene of up to about eightcarbon atoms; and wherein the dispersant is the reaction product of atleast one acylating agent selected from the class consisting ofpolymerized olefin-substituted mono- or dicarboxylic acid or chlorinatedpolymerized olefin-substituted mono- or dicarboxylic acid, or the loweralkyl esters, acyl halides, or anhydrides, of those containing at leastabout thirty aliphatic carbon atoms in the carboxylic acid moiety withat least one alkylene polyamine having up to about ten amino nitrogenatoms wherein the ratio of acylating agent to alkylene polyamine in thereaction mixture is from about one equivalent of acylating agent perequivalent of alkylene polyamines to about one equivalent of acylatingagent to about one mole of alkylene polyamine; and wherein the solventis a normally liquid aromatic hydrocarbon.
 16. A composition accordingto claim 15 wherein n is 0, 1, 2, or 3, each R is independently H,hydrocarbyl of up to about eight carbon atoms, or a monocarboxylic acidacyl radical of up to about twelve carbon atoms, with the proviso thatat least one R variable is an aliphatic monocarboxylic acid acylradical, and R'' is alkylene of up to about eight carbon atoms andwherein the dispersant is the reaction product obtained by reacting atleast one polyisobutenyl-substituted or chlorinatedpolyisobutenyl-substituted succinic acid or anhydride with an ethylenepolyamine.
 17. A composition according to claim 16 wherein one R isalkyl and the other is lower alkanoyl and the dispersant is the reactionproduct of at least one polyisobutenyl-substituted or chlorinatedpolyisobutenyl-substituted succinic acid or anhydride and an ethylenepolyamine having from two to six amino nitrogen atoms in the moleculesthereof wherein the succinic acid or anhydride and the ethylenepolyamine are reacted in an equivalent ratio of about 1:1 to about 1:3,and wherein the solvent is at least one alkyl-substituted benzenecontaining up to 12 carbon atoms.
 18. The method according to claim 17wherein oxy compound is the acetic acid ester of ethylene glycolmonobutyl ether.